index rebuild question

My index needs rebuilding so I analyzed it and based on the information from the index_stats, the pct_used was 81% so I decided to rebuild it.
After rebuilding it, I decided to analyze it again to make sure that pct_used column of the index_stats is good. After analyzing it again, Irealized that the pct_used column has not changed.
I thought that after rebuilding the index the pct_used column of index_stats would change. Am I wrong? Or I'm doing something wrong
Below are the steps that I followed:


1.
analyze index BOB.PK_NEWSTABLE validate structure;

2.
SQL> select name,btree_space,used_space,pct_used from index_stats;


NAME BTREE_SPACE USED_SPACE PCT_USED
------------------------------ ----------- ---------- ----------
PK_NEWSTABLE 58532 47046 81

3.
ALTER INDEX BOB.PK_NEWSTABLE REBUILD storage
(initial 4M next 4M pctincrease 0)
tablespace news_ind_tbs;

4.
SQL> analyze index BOB.PK_NEWSTABLE validate structure;

Index analyzed.

5.
SQL> select name,btree_space,used_space,pct_used from index_stats;

NAME BTREE_SPACE USED_SPACE PCT_USED
------------------------------ ----------- ---------- ----------
PK_NEWSTABLE 58532 47010 81

Find the ratio '(del_lf_rows_len/lf_rows_length)*100'. This is the ratio you might have to observe.

http://otn.oracle.com/docs/products/...2292.htm#10867

I prefer to look at (del_lf_rows/lf_rows)*100 to see how much of my index is empty.

OK like you guys suggested I used del_lf_rows_len and lf_rows_length and below is the result that I got.

Deleted Used % Deleted
Index Name Leaf Rows Leaf Rows Leaf Rows
------------------------------ --------- --------- ----------
PK_NEWSTABLE 0 1613 .00000


QUESTION: From the above results what is the best way to determine if the index needs to be rebuild?

Quote:

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Originally posted by marist89
[url]
I prefer to look at (del_lf_rows/lf_rows)*100 to see how much of my index is empty.

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